Strand reeling apparatus



April 5, 1960 Filed Nov. 28, 1956 T. T. BUNCH STRAND REELING APPARATUS 4 Sheets-Sheet 1 ATTORNEY April 5, 1960 T. T. BUNCH STRAND REELING APPARATUS 4 Sheets-Sheet 2 Filed Nov. 28, 1956 INVENTOR. 7. 73 BUNCH i & .Q.

ATTORNEY April 5, 1960 T. T. BUNCH STRAND REELING APPARATUS 4 Sheets-Sheet 3 Filed Nov. 28, 1956 PRESSURE IN CONDUIT 67 FOR LAMINAR FLOW IN RESISTOR 85 PRESSURE IN- CONDUIT 67 FOR TURBULENT FLOW IN RESISTOR 85 OPERATING RANGE INTERCEPT AT 534 RR M.

760 (OJQROTATIONAL SPEED OF TAKEUP REELQRPM) FIG. 7

o m NT 0. n a ,2 WE www 0 W wm N R F D O E DA T R T 0P cu MN MO FR m a T 0 o O m m 5 omm TQb uaomoh. 935

O i o o o o 8 0 0 4 u E u O 4 3 2 .l o

a: adv U92 5 PRESSURE (P. 51.) INVENTOR.

FIG 3 7'. 7T BUNCH BY H AITORNEV April 5, 1960 Filed Nov. 28, 1956 TORQUE (FT-LBS 4 Sheets-$heet 4 4O I V I I l i l20- 1 I SHAFT TORQUE I I OF HYDRAULIC MACHINE (so) I FOR ILLUSTRATIVE I EXAMPLE I i 80" l l l I X I 60- I l I l u n CURVE A I i 40 OPERATING pi RANGE I 20- I INTERCEPT AT I 523 R.P. M. sea RPMXII s41 RPMM l I l 0 I60 260 .300 400 soo s00 70 e00 900 (my ROTATION SPEED OF TAKEUP REEL (R.P.M.)

' FIG. 6

E 60 8 E ,40 L.

.1 Z 20 2 O z 460 800 I260 I400- INVENTOR. SHAFT ROTIONAL SPEED (RPM) 7- r FIG. 5

BY (LC.

United States Patent O 2,931,588- STRAND REELING APPARATUS Tillman T. Bunch, near Ashland,-Md., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application November 28, 1956, SerialNo. 624,866

7 Claims. (Cl. 242-25) This invention relates to strand reeling apparatus, and more particularly to apparatus forcontrolling the tension on a strand being wound upon a takeup reel.

In the manufacture of communications cables a plurality of insulated conductors are twisted. together to form v a composite cable core which may be taken up continuously upon a takeup reel. In one type of apparatus for fabricating such cable cores, the finished cable coreis wound upon a takeup reel by a cup-like fiyer, the takeup wound upon the takeup reel, may be controlled by suit- 7 able braking means operatively connected to the takeup reel. It is desirable that this tension remain substantially constant at a predetermined value throughout the entire reeling operation.

g It is an object of this invention to provide new and improved strand reeling apparatus.

It is another object of this invention to provide new and improved apparatus for controlling the tension on a strand being wound upon a takeup reel.

It is a still further object of the invention to provide hydraulic means to maintain a constant tension on a strand during the reeling "thereof. I v An hydraulic apparatus for reeling strand, being advanced at a predetermined linear speed, embodying certain principles of the present invention, may include a fiyer mounted rotatably, coaxially of a rotatable reel and means for driving either the fiyer or the reel. A constant-displacement hydraulic machine is provided for applying torque to either the reel or the fiyer, whichever is not being driven by the drive means directly, but which is being driven by the drive means through successive portions of the strand extending between the fiyer and the reel. Means for removing fluid from the constant-displacement machine at a predetermined rate and a fluid resistance of a predetermined value are connected to the exhaust side of the machine. The fluid exiting from the constant-displacement hydraulic machine, in excess of a predetermined amount per unit length of time, is directed through the fluid resistance'to resist the rotation of the constant-displacement machine by the forces transmitted through the successive portions of the strand extending between the fiyer and the reel. In this way, a desired amount of tension is maintained on the strand being advanced at a predetermined linear speed between the fiyer and the reel, as a result of the torque developed by the machine.

A complete understanding of the invention may be had from the following detailed description of apparatus forming a specific embodiment thereof, when read in conjunction with the appended drawings, in which! ice" 2 Fig. 1 is a plan view of the strand reeling apparatus with a portion thereof broken away for clarity;

Fig. 2 is a diagrammatic view ofthe fiyer, takeup reel 7 and associated hydraulic braking system;

Figs. 3, 4 and Sare' graphs showing the operatingcharacteristics of twohydraulic machines used in an illustrative example, and i v 1 Figs. 6 and 7 are graphs showing certain characteristics of the hydraulic system.

Referring now to the drawings and to Fig. l in particular, there is shown takeup apparatus for reeling up a cable core 11 composed of a plurality of insulated conductors which have been twisted together by suitable stranding apparatus (not shown). After leaving the stranding apparatus, the cable core 11 advances from left to right, as viewed in Fig. l, at a constant predetermined linear speed to the takeup apparatus. The takeup apparatus is designed to reel the finished cable core 11 upon a takeup reel 15 forming a part thereof. The takeup apparatus includes additionally a hollow, cup-like fiyer 1.8 which is secured fixedly at its closed. end to a hollow, rotatable shaft 26 for rotation concentrically about the longitudinally extending rotational axis of the takeup reel 15. The shaft 20 is supported rotatably by spaced bearing blocks 22 and 23 mounted on support 24.

As viewed in Fig. 1, the cable core 11 advances longitudinally from left to right through the hollow shaft 20 to a freely rotatable, grooved, guide-sheave 25 mounted partly within a slot 19 formed in the shaft 29. The guide sheave 25 is supported eccentrioally with respect to the rotational axis of the shaft 20 by suitably counterweighted arms 29-29 which are secured fixedly to the shaft for rotation therewith. The guide sheave 25 directs the ad vancing cablev core 11 to a pair of longitudinally spaced, freelyrotatableguide pulleys 3t) and 3l mounted on the outer periphery of the fiyer 18... The cable core 11 travels over the guide pulleys 30 and 31 and is directed inwardly through an aperture 34 formed in the fiyer 18 to the winding surface of the takeup reel 15.

The takeup reel 15 is supported detachably on the free end of a rotatable arbor 35 which is mounted in cantilever fashion on spaced bearing blocks 37 and 38. The bearing blocks 37 and 38 are mounted fixedly to a movable distributor carriage, indicated generally by the numeral 40. The longitudinally extending, rotational axis of the arbor 35 is aligned coaxially with the rotational axis of the fiyer 18 so that the takeup "reel 15 is positioned concentrically with respect to the fiyer.

The distributor carriage 40 is provided with eight pairs .of opposed rollers 4242 engaged rollingly for longitudinal movement along a pair of spaced, longitudinally extending, triangular-shaped tracks 4545 which are supported horizontally by spaced support columns 47-47. A suitable distributor drive, unit, indicated generally by the numeral 50, is operatively connected to the distributor carriage through a vertical shaft drive 51, a pinion 52 and a rack 53, to reciprocate the distributor carriage 4d and thereby move the takeup reel 15 axially into and out of the open end of the fiyer 18 to distribute the convolutions of the cable core 11 being wound upon the talteup reel 15 uniformly across the winding surface thereof. I

Throughout a reeling operation, in which the cable core 11 is wound upon the takeup reel 15, the latter is rotated by the fiyer 18 through the pull of the cable core 11 extending from the fiyer to the winding surface of the takeup reel 15. The 'flyer 18 is driven continuously at a predetermined constant speedby a constant-speed, elec tric drive machine 55. The drive machine 55 is connected through a non-slipping,'toothed, drive belt 56 to a longitudinally extending rotational drive shaft 57 which,

in turn, is connected through non-slipping, toothed, drive belt 59 to a pulley connected to the flyer-supporting shaft 20.

'Mounted near the rear of the distributor carriage 40 is a conventional constant displacement hydraulic machine 60 having an input shaft 62 operatively connected to the arbor 35 through a coupling 65'for positive rotation with the arbor; Communicating with an exhaust port 66 of the hydraulic machine 60 is a flexible conduit 67 and communicating with an intake port 68 of the hydraulic machine 60 is a flexible conduit 69. The conduit 67 communicates with an intake port 71 (Fig. 2) of a second constant displacement hydraulic machine 72 having .an input shaft 73 connected for positive rotation with a constant speed electric machine 75. An exhaust port 76 :of the hydraulic machine 72 is connected to the intake port 68 of'the hydraulic machine 60 through the conduit 69. A reservoir 80 having a vent 70 to atmospheric pressure and containing a supply of hydraulic fluid 82, a fluid resistor 85, and a check valve 90 allowing flow in only the direction indicated, are connected by sections 78-78 of conduit in series and between the conduits 67 FS 1 (l) 1 where:

T=Braking torque (lbs.)

w =Rotational speed (r.p.m.) of the flyer 18 w =Rotational speed (r.p.m.) of the takeup reel 15 F=Tension on the cable core 11 (lbs.)

S=Linear speed of cable core'll (f.p.m.)

The term in the above relationship is a constant since the tension (F) on the cable core 11 and the linear speed (S) of the cable core have been assumed to be constant.

From the above relationship, for any given actual valuesof m F and S, the braking torque required for a desired constant tension on the cable 11 at any rotational speed (w of the takeup reel 15 may be calculated. Referring to Fig. 6, there is shown, merely by way of an illustrative example, a curve designated A which represents a plot of the rotational speed (to of the takeup reel versus the required braking torque (T) for the following possible conditions:

S=1000 f.p.m. w,=1000 r.p.m.

F==125 lbs.

Assume further, for the illustrative example, that the winding diameter of the takeup reel 15, at the empty reel condition (eg. before a strand is wound on the reel), is approximately one foot and that it builds up to approximately two feet at the full-reel condition. If the strand 11 is tc'be wound on the takeup reel 15 and without some slack occurring then the 1000 feet per minute of core 11 that is being delivered to the reeling apparatus mustbe all wound on the reel in any given minute. Since the circumference of the reel 15 at empty reel is 11- or 3.14 feet, then the relative speed of the reel 15 with respect to the flyer 18 must be or 318 r.p.m. Since the reel 15 is rotating slower than the flyer, its speed will be 1000 r.p.m. minus 318 r.p.m. or 682 r.p.m. at the empty takeup reel condition. A similar calculation gives 841 r.p.m. for the full reel speed. Because the winding diameter will increase step by step between these two speeds the rotational speed of the reel will also increase step by step throughout the winding operation. Referring again to Fig. 6, it may be seen that the rotational speeds of the'takeup reel 15 at the empty reel condition and the full reel condition have been indicated on curve A by the designation X and X, respectively. 7

Curve A (Fig. 6), which represents the plot of the takeup reel speed (00,-) versus the required braking torque for a constant strand tension of 125 lbs., may be approximated very closely within the range of the winding opera- .tion from the fempty reel condition X to the full reel condition X by'a straight line, such as, for example, a straight line drawn through and including the points X and X', respectively.

The operating characteristics of the hydraulic machines 60 and 72 are illustrated graphically in Figs. 3, 4 and 5. The characteristics illustrated are within the range of commercially available machines and have been estimated from data for Geroter type 0-30 hydraulic pump described on page 4 of Catalog G-l03 of the Geroter May Corporation, Baltimore, Maryland. Using the torque "friction torque added plotted in Fig. 4, curve A of Fig. 6 may be translated into curve B of Fig. 7, which represents the pressure across the ports of machine '60 vs. rotational speed of that machine which is equal to w, of the takeup reel. The pressure across machine 60 normally is equal to the gauge pressure in conduit 67 because the pressure in conduit 69 normally is atmos 'pheric and, therefore, the ordinate of Fig. 7 is merely designated pressure. Likewise, in Fig. 7, the straight line X-X' is shown in terms of pressure and rotational speed. The straight line XX (Fig. 7) may be extended so as to intercept the abscissa at a point whereat the takeup reel speed (01,.) is 534 r.p.m. The latter speed will be referred to as zero-pressure speed."

As mentioned previously the straight line XX' closely approximates the desired takeup-reel-speed versus required-braking-torque curve within the range of the winding operation from the empty reel condition X to the full reel condition X. Thus, a substantially constant tension will be maintained on the strand if operating conditions-at the'hydraulic machine 60 are as set out below.

In order to achieve a zero pressure at machine 60 when the machine 60 is driven at 534 r.p.m. bythe takeup reel 15, the machine 72 is driven also at 534 r.p.m. to deliver the 27.6 g.p.m. of hydraulic fluid required by the machine 60. lt will be noted that the machine 72 is driven by the constant speed electric machine 75 which, therefore, maintains the theoretical or nominal flow through machine 72 at 27.6 g.p.m. throughout the winding operation. Accordingly, as the takeup reel speed increases above 534 r.p.m., the machine 60 will operate to pump additional fluid from the reservoir and will return some of thfs additional fluid to the reservoir 80 via the fluid resistor 85, developing an increase in the pressure in line 67 above the pressure in line 69. However, as'the pressure increases across the ports 66 and 68, the substantially equal increase across the ports 71 and 76'will cause the machine72 (acting as a fluid machines.

Q =fluid flow through machine 60 Q =fluid flow through resistor 85 Q =fluid flow through machine 72 (acting as a motor) However, when the takeup reel speed is 534 rpm. Q =0 because there is no pressure drop across the resistor. Therefore, at that condition the values of Q and Q may be determined. For the illustrative example The theoretical or nominal value of Q will remain at 27.6 g.p.m. for all values of takeup reel speed and, therefore, the actual value of Q in the above Equation 2 can be determined for empty and full takeup reel conv ditions because the pressure and, therefore, leakage through machine'72 is known at those conditions. It will be noted that the leakage through the machine 72 is the equivalent of the action of a resistance in parallel with resistance 85. Q can also be determined at those conditions from the given characteristics of the hydraulic Using the above Equaton 2 Q can be determined for both empty and full takeup reel conditions. For the illustrative example Q at empty takeup reel=4.8 g.p.m. and Q at full take up reel=9.9 g.p.m.

However, if laminar fluid flow through the resistor is assumed, the following is also true:

wherein: in

p=gauge pressure in conduit 67 (p.s.i.) C =a constant representing the fluid resistance of the resistor (p.s.i./g.p.m.)

-Q =fluicl flow through the fluid resistor 85 (g.p.m.)

Since p and Q have already been found for two conditions (i.e. empty and full takeup reels) it is possible to solve and check the value for the characteristic C of the flu'd resistor that will maintain the line X-X' at the desired slope. For the illustrative example the value of C =73.l p.s.i./g.p.rn.

Assuming that the particular hydraulic fluid used in the illustrative example is an oil having a specific gravity of .90 and a Saybolt viscosity of 300 at a temperature of 20 C. and that a fluid resistor 85 comprising a length of /2 inch diameter-stainless steel tubing is utilized, the calculated length of tubing required to obtain the desired value of C -73.l-p.s.i./g,p.rn. will be 284. feet;-

is illustrated in Fig. 2, this length of tubing is to be formed in a coil due to the relatively large length in- .volved.

It will be recalled that Reynolds number, which is used as the criterion for determ'ning whether or not laminar or turbulent flow conditions exist, depends upon the velocity, viscosity and mass density of the hydraulic fluid and also the pipe diameter, and where the curvature of the path is not a factor may be expressed as;

=BZ M wherein: f

RN=Reynolds number p=mass density of fluid V=fiuid velocity d=pipe diameter =viscosity If RN has a value smaller than 2000 then there is laminarflow present. Determining Reynolds number for the conditions present in the resistor 85 at full reel condition for the illustrative example gives a value of 148,

well under the limit of 2000 and, therefore, the-Formula 3 holds true.

An additional factor which must he considered is the dissipation of heat due to the energy losses in the fluid resistor 85. This heat must be dissipated at a rate sufficient to prevent substantial changes in the temperature of the fluid resistor and the hydraulic fluid, which wouldaflect'the physical properties thereof. Hence, it is desirable to use a heat exchanger, such as a tubular cooling jacket 84, concentrically surrounding the coiled tubing comprising the fluid resistor '85. A cooling medium is continuously circulated through the outer tubular vcool.'ng jacket 84 at'a-predetermined rate suflicient to maintain the hydraulic fluid within the fluid resistor 85 at a normal temperature. Use of a large length of fluid resistor 85, as shown in the illustrative embodiment, makes possible more complete cooling, yet when suitably coiled can produce turbulent flow in place of laminar flow. f

In the illustrative embodiment laminar flow through the fluid resistor 85 was assumed, however, even more desirable results may be achieved if the fluid resistor-.85 is chosen so that'certain states of turbulent flow may be produced therein. Turbulent flow in the resistor 85 would be desirable wheres lesser variation from the desired constant value .of tensionin the strand 11 is required between empty and full'takeup reel conditions. One method of producing'such turbulent flow might be to reduce the diameter of the fluid resi"tor 85 to a value, for example, a suflicient amount less than that of the illustrative embodiment. Such a diameter reduction will also result in a decrease in resistor length which may be desirable in some applications. 'A better method of producing turbulent flow is to form the fluid resistor in a small radius coil as pictured in Fig. 2. The chart below gives the conditions present for the illustrative embodiment if the resistor 85 is designed to produce turbulent flow. These values have been shown in a curve on Fig. 7 and illus t-rate the desirableeffects of turbulent flow over laminar It will be noted that for a situation in which the ratioof full to emptyVwinding diametersis greater than 2:1 the use of turbulentflow'in resistor 85 will be evenmore desirable because thetcurve .representing constant tension, for example, cure A Fig. 6, will be lessreadily approximated by a straight line (i.e w, will vary over a greater range).

'When starting the apparatus, the dyer 18 conceivably could be accelerated to operating speed at a faster vrate than machine 60 could beaccelerated to operating speed. Such a situation would causeexcessive tension in the strand 11 until the apparatus would have reached normal operating conditions; 'The likelihood of such a condition occurring is lessened by checkvalve which. prevents any fluid delivered by machine '72 to the conduit 69 from flowing through the conduit 78. Thus, all the energy delivered by machine 72 is used to accelerate the machine 60 during the starting of-the apparatus. A second function of check valve 90 is to prevent possible cavitation in the-fluid system at such time as the pressure in conduit 69 s greater than the pressure in conduit 67.

Operation Assuming that it is desired to windthe strand 11 upon the reel 15, the strand 11 is threaded through the hollow sha t 20, aro nd he heaves- 39 n an is a tached to the winding surface of the reel 15. The machines 55 and 75 are accelerated to operating speed, thus also bringing the apparatusconnected tothose machines to operating speed. The function of the check valve 90 during the starting operation has already been explained.

At normal operating speeds the flyer '18 will be rotating faster than the reel 15 and will tend to rotate the reel 15 by the pull of the strand extending between the reel 15 in the conduits 67 and 69 and resistor 85 would tend to establish. Therefore, the machine 72 acts as a fluid motor being driven by the fluid passing therethrough from the conduit 67 to conduit 69' and, as a result, ma-

chine 75 is driven and acts as a generator. Machine 72 also tends to leak an amount of fluid therethrough because of the pressure drop across the ports of the machine. The high pressure in conduit 67 relative to conduit 69 also causes a certain amount of the fluid to flo'w from conduit 67 into conduit 78, through resistor 85 and reservoir 80, and thence to conduit 69.

As the winding diameter of the reel 15 increases, the torque exerted on the reel 15 by the strand 11 also increases because of the greater moment arm. This situatio'n results in a greater amount of torque being delivered to the machine 60 which in turn pumps a greater amount of fluid therethrough from conduit 69 to conduit 67. A greater pressure drop across these conduits results from the fact that machine 72 is maintaining a constant speed and also from the fact that an increased flow in resistor 85 results in an increased pressure drop thereacross. Because the constant speed of the machine75 and the amount of resistance in the resistor 85 were preselected, the increased torque in the shaft 35 merely results in a substantially equal force or tension in the strand 11.

Meanwhile as each layer of strand is wound on the reel 15, the distributor carriage 40 isdriven through one stroke by the drive unit 50. Thus, the reel moves axially into and out of the open end of the flyer 18 so as to distribute the convolutions of the cable core 11 uniformly across the winding surface of the reel 15. After the reel 15 has been completely wound to the full reel" condition, the machines 75 and 55 are stopped, the full reel is removed and replaced with an empty one and the operation is repeated as above-described.

When a flow source" or constant flow source" is referred to herein, the meaning is intended to be analogous to that used when referring to a current source" or a constant current source in electricity and, in the case of constant flow source" would, therefore, mean that the flow through such a source would remain constant no matter what the pressure thereacross.

Other arrangements embodying the principles of the invention, and falling within the spirit and scope thereof, can be provided by those skilled in the art. For example, it would not be necessary to drive the machine 72 by a constant speed machine 75 assuming that an alternative motor maintained a constant speed-torque proportion as the torque upon the motor is increased during the winding operation. Moreover, the hydraulic system might be operated as a pressurized closed system rather than with a reservoir vented to atmosphere as illustrated. Furthermore, it can be seen that the characteristics of the machine 72 do not have to be identical to those of machine 60. Other conventional constant displacement machines could; be used in the place of machine 72. -Therefore,'it is manife'stthat the above-de- 8 scribed arrangements are merely illustrative embodiments of the invention. i

What'is claimed is:

1. Hydraulic apparatusfor reeling strands comprising flyer means, means for driving said flyer means at a constant speed, a takeup reel rotatably mounted coaxially of said flyer means, a constant displacement hydraulic machine having an intake port and an exhaust port and having a shaft connected operatively to said takeup reel, conduit means connected to the intake and the exhaust ports, a flow source of predetermined value interposed in said conduit means, and fluid resistance of a predetermined value connected in parallel with said source and across said conduit means, whereby, as a strand is delivered at a constant linear speed to said rotating flyer means and hence to said rotating reel, the torque developed by said machine acting through said reel main tains a constant tension on the strand. 7

2. Hydraul'c apparatus for reeling strands comprising flyer means, a takeup reel mounted coaxially of said flyer means, means for driving the flyer means at a substantially constant speed, a constant displacement hydraulic machine having an intake conduit and an exhaust conduit and having a shaft connected operatively to said takeup reel, a constant flow source of predetermined value connecting said conduits, and a resistance of predeterm'ned value connected in parallel with said source and across said conduits, whereby, as the strand is delivered at a constantlinear speed to said rotating flyer means and thence to saidreel, the braking torque of said machine acting through said reel maintains a substantially constant tension on the strand.

3. Strand reeling apparatuscomprising a flyer operable at'a constant rotatfonal speed, a takeup reel rotatably mounted coaxially of said flyer, a first rotary constant displacement'hydraulic' machine having an intake conduit and an exhaust conduit and having a shaft connected to said takeup reel for positive rotation therewith, a second rotary constant displacement hydraulic machine having an exhaust port connected to said intake conduit of said first machine and having an intake port connected to said exhaust conduit of said first machine, means for driving said second machine at a predetermined, substantially constant speed, and a fluid resistance of predetermined value connect ng said intake conduit and said exhaust conduit, whereby, as a strand is delivered at a substantially constant linear-speed to said rotating flyer and thence to said reel, the torque developed by said first machine acting through said reel maintains a constant tension on the strand.

4. Strand reeling apparatus for maintaining constant tension on a strand being wound upon a takeup reel comprising a flyer operable at a constant rotational speed, a takeup reel rotatably mounted coaxially of said flyer, a constant displacement hydraulic machine having a shaft connected to said takeup reel for positive rotation therewith, said machine having an intake port and an exhaust port, a second constant displacement hydraulic machine operable at a constant speed and having an intake port and an exhaust port, a fluid conducting means connecting the exhaust port of the first machine and the intake port of the second machine, a second fluid conducting means connecting the intake port of the first machine and the exhaust port of the second machine, a fluid resistor, a reservoir, and a check valve, said resistor, said reservoir and said check valve connected inv that order and in series from said first-mentioned fluid conducting means to said second-mentioned fluid conducting means, whereby, as a strand is delivered at a substantially constant linear speed to said rotating flyer and thence to said reel, the torque developed. by said first machine acting. through said reel maintains a constant tension on the strand.

5. Strand reeling apparatus for maintaining a constant tension on a strand being wound upon a takeup reel comprising a flyer operable at a constant rotational speed, a takeup reel rotatably mounted coaxially of said flyer, a constant displacement machine operatively connected to said reel and having an intake conduit and an exhaust conduit, a constant flow source of predetermined value connecting said conduits, and a resistance of predetermined value connected in parallel with said source and across said conduits so as to produce turbulent flow within said resistance during operation of the apparatus, whereby, as the strand is delivered at a constant linear speed to said rotating flyer and thence to said rotating reel, the braking torque of said machine acting through the reel maintains a constant tension on the strand.

6. Strand reeling apparatus for maintaining constant tension on a strand being wound upon a takeup reel comprising a flyer operable at a constant rotational speed, a takeup reel rotatably mounted coaxially of said flyer, a first rotary constant displacement hydraulic machine having an intake conduit and an exhaust conduit and having a shaft connected to said takeup reel for positive rotation therewith, a constant speed machine, a second rotary constant displacement hydraulic machine connected between said conduits and having-a shaft connected to said constant speed machine for positive rotation therewith, a fluid resistor of predetermined value connected to said exhaust conduit, a check valve connected to said intake conduit so as to allow flow therethrough only towards said intake conduit, and a fluid reservoir connected between said resistor and said check valve, whereby, as a strand 'is'delivered at a substantially constant linear speed to said rotating fiyer and thence to said reel, the torque developed by the first hydraulic machine act- 10 ing through said reel maintains a constant tension on the strand.

7. Hydraulic apparatus for reeling strand being advanced at a predetermined linear speed, which comprises flyer means, reel means connected operatively mechanically to said flyer means solely by the strand extending therebetween, means for driving one of the first two mentioned means rotatably, a constant-displacement hydraulic machine having an intake port and an exhaust port and having a shaft connected operatively to the other of said first two mentioned means, conduit means connected to the intake and the exhaust ports, a fluid resistance of a predetermined value connected by said conduit means to said exhaust port, and means connected to said conduit means for diverting fluid exiting from said machine away from the entrance of said resistance at a predetermined rate, whereby as a strand is advanced at a predetermined linear speed between said flyer and said rotating reel the torque developed by said machine, acting through the means to which the shaft is connected operatively, maintains a predetermined tension on the strand.

References Cited in the file of this patent UNITED STATES PATENTS 2,351,669 Dentzer et 1. June 20, 1944 2,655,060 Spencer Oct. 13, 1953 2,716,007 Scott Aug. 23, 1955 2,753,688 Bunch July 10,1956

FOREIGN PATENTS 528,841 Canada Aug. 7, 1956 

